Interferometric Feedstock Imaging for Laser Penetration Control
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Solution Overview
Problem
Current laser technologies face challenges in achieving precise axial control during material processing, particularly in surgical and industrial applications, due to limitations in controlling the depth of laser beam penetration, leading to issues such as unintended tissue damage and weld porosity.
Innovation Solution
An apparatus and method utilizing an optical interferometer to produce an interferometry output based on optical path lengths, which is used to control processing parameters of the material modification process, enabling real-time feedback and precise control of the material processing beam.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If laser power is increased to improve processing speed, then productivity is improved, but harmful effects worsen
Solution Approach 1:
The system uses real-time sensing (OCT, pyrometry, or other non-contact methods) to monitor penetration depth and thermal effects during laser processing. When the target depth is reached or thermal damage thresholds are approached, the system automatically reduces power or stops irradiation, enabling high processing speeds without causing unintended damage to surrounding tissues or materials
Solution Approach 2:
The patent employs pulsed laser delivery with dynamically adjusted pulse duration and repetition rate based on real-time feedback. This allows high average power for fast processing while using short pulses to confine energy deposition, preventing thermal diffusion and unintended damage to surrounding areas
2Length of moving object
If laser beam is used for deep penetration, then processing depth is improved, but measurement precision deteriorates
Solution Approach 1:
The system implements real-time depth measurement using optical coherence tomography (OCT) or interferometric techniques that provide micrometer or sub-micrometer precision depth feedback during laser drilling or cutting. This feedback is used to dynamically adjust focus position and power to maintain precise depth control even at deep penetration levels
Solution Approach 2:
The patent introduces an intermediary measurement system (OCT probe or sensor) that independently measures penetration depth without being affected by plasma, smoke, or turbulence in the laser path. This intermediary provides accurate depth information that feeds back to control the laser, enabling precise deep penetration while maintaining measurement accuracy
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution allows for precise control of the material processing beam, improving axial control during laser surgeries and industrial processes, reducing unintended tissue damage and weld porosity, and enhancing the reliability and quality of laser-based operations.
Implementation Method 1
an optical interferometer that produces an interferometry output using at least a component of the imaging light that is delivered to the sample, the interferometry output based on at least one optical path length to the sample compared to another optical path length
Data Source
AI summary
Methods and systems are provided for using optical interferometry in the context of material modification processes such as surgical laser, sintering, and welding applications. An imaging optical source that produces imaging light. A feedback controller controls at least one processing parameter of the material modification process based on an interferometry output generated using the imaging light. A method of processing interferograms is provided based on homodyne filtering. A method of generating a record of a material modification process using an interferometry output is provided.